The spatiotemporal development of adipose tissue

Adipose tissue is a structure highly specialized in energy storage. The adipocyte is the parenchymal component of adipose tissueand is known to be mesoderm or neuroectoderm in origin; however, adipocyte development remains poorly understood. Here,we investigated the development of adipose tissue by analyzing postnatal epididymal adipose tissue (EAT) in mouse. EAT wasfound to be generated from non-adipose structure during the first 14 postnatal days. From postnatal day 1 (P1) to P4, EAT iscomposed of multipotent progenitor cells that lack adipogenic differentiation capacity in vitro, and can be regarded as being inthe 'undetermined' state. However, the progenitor cells isolated from P4 EAT obtain their adipogenic differentiation capacity byphysical interaction generated by cell-to-matrix and cell-to-cell contact both in vitro and in vivo. In addition, we show thatimpaired angiogenesis caused by either VEGFA blockade or macrophage depletion in postnatal mice interferes with adiposetissue development. We conclude that appropriate interaction between the cellular and matrix components along with properangiogenesis are mandatory for the development of adipose tissue.